GB2053971A

GB2053971A - Corrosion protection of easy-open can end

Info

Publication number: GB2053971A
Application number: GB8019845A
Authority: GB
Original assignee: USS Engineers and Consultants Inc
Current assignee: USS Engineers and Consultants Inc
Priority date: 1979-06-29
Filing date: 1980-06-18
Publication date: 1981-02-11
Also published as: JPS5632229A; FR2460259A1; DE3023651A1; US4215794A

Description

1

GB 2 053 971 A 1

SPECIFICATION Easy-open can end

This invention relates to an easy-open can end.

The invention is particularly useful for cans in 5 which the segment cut from the can end remains attached when the can is opened, thus forestalling littering. Usually, the ends of such cans are aluminum, and they have a score line which defines a segment to be punched inwardly of the 1 o can. A tab is riveted to the can end adjacent the score line and may be lifted to apply leverage to the material within the score line, and thus punch it inwardly.

There is a problem in constructing a tab which 15 has sufficient mechanism strength and yet does not corrode. A special aluminum alloy has been used, but is in short supply. Tinplate has not been satisfactory because a tinplate tab rusts around its exposed untinned edges. Zinc-coated steel has 20 been used, but shows unsightly white rust unless lacquered.

An object of the invention is to provide an easy-open can end having a tab which can be formed either of tinplate or blackplate, but does not rust. 25 According to the present invention, there is provided an easy-open can end which carries a tab for punching a portion of the can end inwardly to open the can, the tab having an anodic insert to prevent corrosion of the can end or tab. 30 The invention is further described, by way of example, with reference to the accompanying drawings, in which:—

Figure 1 is a top plan view of a can of the type to which the invention is applicable;

35 Figure 2 is a vertical section on line II—II of Figure 1, but showing the can opened;

Figure 3 is a bottom plan view of a tab without its anodic insert;

Figure 4 is a bottom plan view of the anodic 40 insert; and

Figure 5 is a bottom plan view of the tab 20 with the insert applied.

Figures 1 and 2 show a portion of an easy-open can which includes an end 10 and a cylindrical 45 side wall 12. The end and side walls may be aluminum, tinplate, or blackplate and may be lacquered or not. The end 10 has a depressed area

13 and a score line 14 within the depressed area. A tab 15 is affixed to the end, preferably with an 50 integral rivet 16, also within the depressed area. The tab itself has an arcuate cut 17 extending part way around the rivet, and a point 18 overlying the area of the end 10 within the score line 14. The tab may be lifted to open the can. The tab comes 55 apart at its cut 17 and bends along a line 19. The point 18 bears downwardly against the area within the score line 14 and thus punches this portion of the end inwardly, as shown in Figure 2. The punched portion remains attached through a 60 neck 20.

In accordance with the invention, a small anodic insert 21 is applied to the underside of the tab 15, as shown in Figure 5. The insert may be of zinc, zinc-plated steel or other anodic material. 65 The insert lies within the area defined by the cut 17 and bend line 18. The insert has a hole 22 to receive the rivet 16. The insert underlies the portion of the tab which remains against the can end when the tab is lifted. Hence, unsightly white 70 rust (zinc oxide) which forms on zinc is hidden from view.

If the tab is tinplate, the insert effectively provides anodic protection to the exposed untinned edges and at the score line. The insert 75 can serve also to protect a blackplate tab or a can end of tinplate or blackplate. Otherwise, a tinplate end is subject to corrosion at the score line.

Claims

1. An easy-open can end which carries a tab for

80 punching a portion of the can end inwardly to open the can, the tab having an anodic insert to prevent corrosion of the can end or tab.

2. A can end as claimed in claim 1, in which said insert is of zinc or zinc-plated steel.

85

3. A can end as claimed in claim 1 or claim 2, in which said insert underlies said tab where it is hidden from view.

4. A can end as claimed in any preceding claim, in which said tab is of tinplate or blackplate.

90

5. An easy-open can end constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.